difftool: Show changes to file contents using an external tool

Usage:
  eg difftool [--tool=] [--unstaged | --staged] [REVISION] [REVISION] [FILE...]

Description:
  Shows differences between different versions of the project using an
  external tool.  By default, it shows the differences between the last
  locally recorded version and the version in the working copy.

  This command behaves just like 'eg diff'; see 'eg help diff' for more
  details.

  You can configure the default external tool with 'eg config'.  You can
  specify the default tool by setting 'diff.tool'; you can configure the
  tool by setting 'difftool..cmd'.  See the 'Configuration File'
  section of 'git help config' for more details.

Example:
  Show local unrecorded changes in vimdiff
      $ eg difftool --tool=vimdiff

  See 'eg help diff' for more diff examples.


Differences from git difftool:
  git difftool behaves just like git diff, but launches an external tool
  instead of using git's built-in machinery.  eg diff is quite different from
  git diff (see 'eg help diff' for details); eg difftool behaves just like
  eg diff.

See also
  Run 'git help difftool' for a comprehensive list of options available.
  eg difftool is designed to accept the same options as git difftool, and
  with the same meanings unless specified otherwise in the above
  "Differences" section.